On the British species of Poly podium. 147 



es in height. It is not uncommon on dry sandy banks. I 

 have seen it in some abundance on Hampstead Heath. 



y. rejlexum. Frond pinnate, pinnce pinnatifid, lobes dentate, concave ; 



colour dark green. 

 6\ dumetorum. Frond twice pinnate, lobes pinnatifid, with terminal, 



sharp, prickly teeth. 

 c. syhestre. (n. v.) Frond thrice pinnate, perfectly triangular, ele- 

 gant, drooping, bright green ; lobes dentate and spined. 

 This plant I believe to be P. spinulosum of Galpine. It is 

 found in thick woods, growing among decayed leaves, &c. 

 f. cataractarum. (n. v.) Frond thrice pinnate, elongate, drooping, e- 

 legant, yellow green ; pinnce distant. 

 This beautiful plant seems to be abundant about the water- 

 falls in Wales ; I have not yet seen it in England. 



rj. spinulosum. Frond sometimes thrice pinnate at the base, but ge- 

 nerally only twice pinnate, with the lobes pinnatifid ; elongate, nar- 

 row, sides parallel as far as the fifth or sixth pair oipinnm^ then with 

 the apex pointed; erect, rigid, spiny, pale sickly green; rachis 

 smoother and paler than in the other varieties. 

 Frequent in thick woods and on moors, growing on dying 

 trees, &c. Certainly grows from the same root as sylvestre 

 and dilataUim. 



6. dilatatum. Frond thin, pinnate ; lobes separate, and often stalked ; 

 rachis long, stout, black, scaly, erect at first, then gracefully droop- 

 ing ; frond sometimes 3 feet in height. 

 Hedge-rows and banks. This appears to be the typical 

 form of the species. 



t. ferax. (n. v.) Frond thrice pinnate ; lobes separate and stalked ; 

 sori confluent, covering the under surface. 

 This variety is somewhat too widely separated from the 

 rest ; but the few dried fronds which have reached London, my 

 friend, Mr. D. Don has seen, and considers them as belonging 

 to the present species, and I bow to his decision. The plant 

 is exclusively Irish, and has the habit of a very luxuriant and 

 fruitful specimen of Asplenium Adiantum nigrum. 



Above I have attempted to describe the striking and con- 

 stant varieties of this very common fern ; but I by no means 

 wish it to be supposed that I consider the list complete. — 

 I have examined, from different sources, a tolerable number 

 of fronds, amounting probably to thousands, and I find a re- 

 gular gradation of form, from the variety which I suppose to 

 be the typical dilatatum of authors, to each of the other va- 

 rieties, with the exception of ferax : a list, therefore, to be 

 complete, should trace this gradation, minutely describing 

 each intervening form. To such a list it must be objected, 

 that excepting with a view of settling some disputed point, it 

 would be a work of useless labour. The variety which our 

 botanists consider of the greatest value, appears to be spinu- 

 losum ; I have fortunately found this plant in profusion, grow- 



